Vancouver Island Avalanche Bulletin

Valid until April 11th 2010.

DANGER RATINGS (Make sure you understand the danger level meanings)

Hazard Timing: Sun on South to West aspects or temperatures above freezing during the day will be the peak hazard times. Some intense flurries may occur in the afternoons.

Confidence: Good with West Coast having higher freezing levels Saturday.

Main Concerns:

• Storm Snow on steep or solar aspects
• Wind Slab and Redistributed WindSlab
• Cornice Fall, North West North North East East aspects (potential large natural trigger).

Weather:

An unsettled week with flurries and mild day time temperatures and cool nights; with a storm that never really came for Wednesday. Despite this we still saw 40 to 60 mm fall Monday through Thursday, with winds that went from East to South to West and even howled from the North...below 1400m the temps did get above freezing except some cold aspects.

More unsettled weather is expected for the Island and a bit on the cool side. Flurries into Friday 10 cm and again in the AM or PM each day getting drier to Sunday mostly sunny. Freezing levels from Surface to 1000m cooler for the North and East  and warmer West. Winds More Westerly except Saturday from the South at 20 or 30 KMH.

Avalanche Activity:

Cornice falls have occurred.  Wind slabs continue to be sensitive to human triggering and avalanche control in isolated and specific terrain. Slabs 20 cm to 1.0 m deep size 1 to 1.5 ; near ridge tops and on cross loaded features including reverse loaded Southerly aspects. Steeper North Facing terrain shed snow with warming this week, triggering size 2 slab below and running to drainage.  Mt Cain Area. Solar activity up in PM with Sun.

Snowpack:

Lots of variation due to wind.  Periodic melting in late March and early April has thrown a few more crusts into the upper pack; especially solar aspects.  Some surface hoar was reported preserved Wednesday Thursday 8th sheltered areas, more surface hoar will form over the weekend. The upper snowpack has generally good settlement but is a bit upside down.  Moderate to Hard shears are found 15 to 45 to 60 down and are more sensitive at higher elevations and colder aspects.  Solar aspects melting and pinwheeling during heat of day.

Cooler temperatures and continued winds are redepositing snow  Saturday/ Sunday Mostly in Alpine winds reloading North and East aspects, with winds from the South and West.

Terrain Discussion: 

Caution over head hazards such as Cornice and very steep slopes. Caution windslab areas especially steeper, harder and thinner slabs West & East.  Caution Solar aspects.

Travel Advisory: 

Watch the temperatures and sun. This time of year the sun becomes a factor and the possibility of rapid temperature increases is noteworthy. Natural triggers such as cornice, tree bombs and steep plastered rock, are active at this time. Human Triggering is Possible to Probable and decreasing into Sunday, in the Alpine in specific areas remain touchy. Avoid travel on or below cornices.  Watch for isolated windslabs. Caution Solar aspects during warming.

Outlook:

More winter with some flurries some breaks and sun. Cooler nights with frost to sea level 500m average F.L.and some warm peaks above freezing possible each day and especially Sat Sun. Winds Light to Moderate West South Saturday and back to West and NW Sunday.